Polynuclear aromatic and chlorinated hydrocarbons in mussels from the coastal zone of Ushuaia, Tierra del Fuego, Argentina.

Mussels (Mytilus edulis chilensis) were collected from 12 coastal locations in Ushuaia Bay, Argentina, and the surrounding area in October 1999 and again in October 2003. Concentrations of polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and selected chlorinated pesticides were determined to assess the impact of a fast-growing population in the area. Total PAH concentrations ranged from 2.24 to an extremely high concentration of 2,420 µg/g lipid measured in mussels collected near an oil jetty used to discharge to shore storage tanks. The composition of PAHs in these samples indicates that the source of these compounds inside Ushuaia Bay is predominantly petrogenic, with some pyrogenic background, whereas mostly pyrogenic-related PAHs were evident in areas outside the bay. Total concentrations of PCBs ranged between 12.8 and 8,210 ng/g lipid, with the highest concentration, detected inside Ushuaia harbor, representing a 10-fold increase when compared with historical data. Chlorinated pesticides were detected at comparatively lower concentrations, with 4-4'- 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene being the most common. The aggressive increase in population and related activities observed in the city of Ushuaia over the last two decades might have affected the environmental quality of the local bay. Moreover, the oceanographic and atmospheric conditions existing in Ushuaia Bay and surrounding areas may favor the accumulation and long-term presence of these organic pollutants in all compartments of this fragile environment.